Composition capable of radiation activated catalysis and radiation curable urethane containing the composition

ABSTRACT

A composition capable of radiation activated catalysis is provided. The composition comprises a metal compound, a mercapto compound and an olefinic compound. Radiation curable urethane compositions comprising the disclosed composition are also provided. The radiation curable urethane compositions comprise the disclosed composition, a hydroxyl compound and an isocyanate compound. Activation of the composition by radiation in a urethane formulation provides for an efficient method of curing the urethane composition. Coating and adhesive compositions comprising the radiation curable urethane compositions are also provided. In addition, methods for coating and bonding substrates are disclosed.

TECHNICAL FIELD

The present disclosure relates to a composition capable of radiationactivated catalysis and a radiation curable urethane compositioncontaining the disclosed composition. The present disclosure alsorelates to coating and adhesive compositions comprising the radiationcurable urethane composition and methods of using the coating andadhesive compositions.

The radiation curable urethane composition is useful in applicationswhere it is desirable for a urethane composition to remain uncured forlong periods of time but then can be rapidly cured upon exposure toradiation. The radiation curable composition offers advantages overtraditional urethane compositions which can prematurely cure over time(short pot life). Slow cure can increase urethane pot life but oftenleads to unacceptably long cure times. The radiation curable urethane ofthe present disclosure provides long pot life and on-demand curing. Theurethane composition offers distinct advantage in applications such asadhesives for flexible packaging and coating applications.

BACKGROUND

Urethanes are produced by the reaction of hydroxyl compounds withisocyanates. The reactions are typically catalyzed with a tin or bismuthcatalyst. When the hydroxyl and isocyanate compounds are mixed in thepresence of the catalyst, the reaction proceeds rapidly to form a curedurethane product. This rapid curing of the urethane requires that theurethane composition be used quickly before the urethane cures leadingto short working times (pot life). Lesser amounts of catalyst can beutilized to lengthen the time it takes for the urethane composition tocure which in turn allows for longer pot life for the composition. Thisapproach can lengthen the cure time such that it slows the production ofproducts that utilize the urethane compositions. Ideally, a urethanecomposition should be storable and usable for a long period then curableon demand.

Approaches that passivate the curing catalyst with a passivating agentthat can be subsequently neutralized are described in U.S. Pat. Nos.4,788,083, 5,478,790, 6,348,121 and 6,548,615. In this approach,neutralization of the catalyst passivator activates the catalyst so thatthe urethane composition can cure. The specific passivating agent andthe mechanism for neutralizing the passivator determine the rate atwhich a urethane composition will cure.

If the passivating agent is not effective enough, the urethane can cureprematurely. If the mechanism for neutralizing the passivating agent istoo slow, then the urethane can cure too slowly. Ideally, the passivatoris effective in inhibiting the catalyst activity for long periods andthe passivator should be capable of being neutralized quickly so thatthe maximum amount of catalyst is available immediately for a fast curetime.

SUMMARY

The present disclosure relates to a composition capable of radiationactivated catalysis which comprises a metal compound, a mercaptocompound and an olefinic compound. The present disclosure also involvesa catalyst that is effectively passivated yet is rapidly activated byradiation. This catalyst is ideal for urethane applications that oftenrequire on-demand curing performance.

The disclosure also relates to a radiation curable urethane comprisingthe radiation activated catalyst. Activation of the catalyst byradiation in a urethane formulation provides for an efficient method ofcuring the urethane composition.

The disclosure further relates to coating and adhesive compositionscomprising the radiation curable urethane composition. In addition,methods for coating and bonding substrates are disclosed.

Still, other objects and advantages of the present disclosure willbecome reading apparent by those skilled in the art from the followingdetailed description, wherein it is shown and described only in thepreferred embodiments, simply by way of illustration of the best mode.As will be realized, the disclosure is capable of other and differentembodiments, and its several details are capable of modifications invarious obvious respects, without departing from the disclosure.Accordingly, the description is to be regarded as illustrative in natureand not as restrictive.

DETAILED DESCRIPTION AND VARIOUS MODES

The disclosed composition capable of radiation activated catalysiscontains a metal compound, a mercapto compound and an olefinic compound.The metal compound alone is capable of functioning as a catalyst invarious reactions including the reaction between a hydroxyl compound andan isocyanate compound to form a cure urethane composition. The mercaptocompound in the catalyst composition acts to passivate the metalcompound by inhibiting its catalytic activity. The catalytic activity ofthe passivated metal compound can be restored by exposing the disclosedcomposition to radiation. The radiation can be actinic radiation such asUV radiation or e-beam radiation. The radiation causes the olefiniccompound to react with the mercapto compound in a thiolene reactionwhich neutralizes the passivating effect of the mercapto compoundallowing the metal compound to become fully active as a catalyst. Thisallows compositions such as a two-part urethane composition to curerapidly due to the radiation induced release of the passivated catalyst.

The metal compound in the disclosed composition can be any compound thatcan provide a catalytic effect in a reaction sequence. The catalyticactivity of the metal compound is also passivated by the presence of amercapto compound. The olefinic compound can be any olefinic compoundthat can react with a mercapto compound in a thiolene type reaction.

Typically, the metal compound is a tin compound, a bismuth compound, agermanium compound, a cobalt compound, a manganese compound or acombination of these metal compounds. More typically, the metal compoundis selected from dibutyltindilaurate, stannous acetate, stannic oxide,stannous octoate, dibutyltin dioctoate, tin mercaptides, stannouscitrate, stannous oxylate, stannous chloride, stannic chloride,tetra-phenyl tin, tetra-butyl tin, tri-n-butyl tin acetate, di-alkyl tindicarboxylates, dimethyl tin dichloride, bismuth tricarboxylates,bismuth nitrate, bismuth halides, bismuth sulfide, basic bismuthdicarboxylates, and mixtures thereof. Typically, the catalystconcentration ranges from about 0.005 to about 0.5 weight % based on thetotal amount of the composition.

In the disclosed composition, the mercapto compounds can be any mercaptocompounds that can passivate the catalytic activity of the metalcompound and that can react with an olefinic compound. Typically, themercapto compound is selected from trimethylol propane tri-(3-mercaptopropionate), pentaerythritol tetra-(3-mercapto propionate), glycoldi-(3-mercapto propionate), glycol dimercapto acetate, trimethylolpropane trithioglycolate, mercapto diethyl ether, ethane dithiol,thiolactic acid, mercapto propionic acid and esters thereof, thiophenol,thio acetic acid, 2-mercapto ethanol, 1,4-butanedithiol, 2,3-dimercaptopropanol, toluene-3,4-dithiol, alpha,alpha′-dimercapto-para-xylene,thiosalicylic acid, mercapto acetic acid, dodecane dithiol, didodecanedithiol, di-thio phenol, di-para-chlorothiophenol, dimercaptobenzothiazole, 3,4-dimercapto toluene, allyl mercaptan, benzylmercaptan, 1,6-hexane dithiol, 1-octane thiol, para-thiocresol,2,3,5,6-tetrafluorothiophenol, cyclohexyl mercaptan,methylthioglycolate, various mercapto pyridines, dithioerythritol,6-ethoxy-2-mercaptobenzothiazole, d-limonene dimercaptan γ-mercaptosilane and mixtures thereof.

Typically, the molar ratio of mercapto groups to metal in the metalcatalyst ranges from about 2:1 to about 500:1.

The olefinic compound in the disclosed composition can be an olefiniccompound that can react with a mercapto compound in a thiolene typereaction. Non-limiting examples include diallyl phthalate, acrylic acid,methacrylic acid alkyl acrylate, alkyl methacrylate, acrylamide andmixtures thereof. The molar ratio of the olefinic groups in the olefinto the mercapto groups in the mercaptan ranges from about 0.5:1 to about2:1.

The radiation activated catalyst is useful in systems requiring thecatalyst to remain inactive until needed. When needed the catalyst canbe activated with radiation and the activated catalyst can quicklycatalyze the desired reaction. An example of such a system is a urethanetype composition which when combined with the radiation activatedcatalyst forms a radiation curable urethane composition.

Typically, urethane compositions contain two reactant parts whichinclude a hydroxyl compound component and an isocyanate compoundcomponent. The hydroxyl component typically contains a metal compoundcatalyst which catalyzes the reaction between the isocyanate compoundand hydroxyl compound. Often it is desirable not to have the hydroxylcompound and isocyanate react immediately so that the urethanecomposition can be utilized for its desired application. After theurethane composition is applied as needed, it is then desirable to curethe urethane quickly. The disclosed radiation activated catalyst fillsthis need by allowing the urethane components to be mixed with minimalcuring and then the urethane components can be cured rapidly byradiation when desired.

The disclosed radiation curable urethane composition contains theradiation activated catalyst, a hydroxyl compound, an isocyanatecompound and optionally other customary components such as extenders,solvents, fillers and the like.

The hydroxyl compound is not limited and can include diol, triols,tetrols and mixtures thereof. Typically, the hydroxyl compound is apolyhydroxy compound, a polyhydroxy oligomer or a polyhydroxy polymer.

Hydroxy compounds useful in the radiation curable urethane compositionsinclude hydroxypolyesters, hydroxypolyethers, hydroxypolythioesters,hydroxypolyacetals, hydroxypolycarbonates, dimeric fatty alcohols,esteramides, polyetherpolyols, polyesterpolyols, polycarbonatepolyols,ethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- and1,3-propanediol, 1,4- and 1,3-butanediol, 1,6-hexanediol,1,8-octanediol, neopentyl glycol, 1,4-bis-(hydroxymethyl)-cyclohexane,bis-(hydroxymethyl)-(tricycle-[5.2.1.0^(2.6)]-decane or1,4-bis-(2-hydroxyethoxy)-benzene, 2-methyl-1,3-propanediol,2,2,4-trimethylpentanediol, 2-ethyl-1,3-hexanediol, dipropylene glycol,polypropylene glycols, dibutylene glycol, polybutylene glycols,bisphenol A, tetra-bromobisphenol A, glycerol, trimethylolpropane,1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol, quinitol,mannitol, sorbitol, methylglycoside 1,4:3,6-dianhydrohexitol andmixtures thereof.

The hydroxy compound also may be a hydroxy urethane prepolymer which canbe a polyol or monomeric alcohol provided from a polyester, polyether,polyurethane, polysulfide, or the like. Ethylenic unsaturation even canbe provided by the monomeric alcohol or polyol itself or can be reactedonto a polyol or monomeric alcohol subsequently by conventional reactionschemes, if such unsaturation is desirable. Conventional reactionschemes call for the reaction of a monomeric alcohol or polyol with, forexample, acrylic acids, acrylyl halides, acrylic-terminated ethers,acrylic or methacrylic anhydrides, isocyanate-terminated acrylates,epoxy acrylates, and the like. Further reaction schemes for formulatinghydroxy urethane prepolymers include reaction of a hydroxy-acrylatemonomer, hydroxy methacrylate monomer, or an allyl ether alcohol with acyclic anhydride such as, for example, the anhydrides: maleic, phthalic,succinic, norborene, glutaric, and the like. Unsaturatedpolyol-polyesters optionally then can be reacted with a suitableoxirane, such as, for example, ethylene oxide, propylene oxide, glycidylacrylate, allyl glycidyl ether, alpha-olefin epoxides, butyl glycidylether, and the like. Suitable allyl alcohols include, for example,trimethylolpropane monoallyl ether, trimethylol propane diallyl ether,allyl hydroxylpropylether, and the like.

The isocyanate compound is not limited and can include aromatic,aliphatic or, mixed aromatic/aliphatic isocyanates and polymericisocyanates. Further, alcohol-modified and other modified isocyanatecompositions find utility in the disclosure. Multi-isocyanatespreferably will have from about 2-4 isocyanate groups per molecule foruse in the coating composition and adhesive composition of the presentdisclosure. Suitable multi-isocyanates for use in the present disclosureinclude, for example, hexamethylene diisocyanate, 4,4′-toluenediisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylpolphenyl isocyanate (Polymeric MDI or PAPI), m- and p-phenylenediisocyanates, bitolylene diisocyanate, triphenylmethane triisocyanate,tris-(4-isocyanatophenyl)thiophosphate, cyclohexane diisocyanate (CHDI),bis-(isocyanatomethyl)cyclohexane (H6XDI), dicyclohexylmethanediisocyanate (H12MDI), trimethylhexane diisocyanate, dimer aciddiisocyanate (DDI), dicyclohexylmethane diisocyanate, and dimethylderivatives thereof, trimethyl hexamethylene diisocyanate, lysinediisocyanate and its methyl ester, isophorone diisocyanate, methylcyclohexane diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate and methyl and hydrogenatedderivatives thereof, polymethylene polyphenyl isocyanates,chlorophenylene-2,4-diisocyanate, and the like and mixtures thereof.Aromatic and aliphatic polyisocyanate dimers, trimers, oligomers,polymers (including biuret and isocyanurate derivatives), and isocyanatefunctional prepolymers often are available as preformed packages andsuch packages are suitable for use in the present disclosure. The ratioof isocyanate equivalents of the polyisocyanate cross-linking agents tothe hydroxyl groups from the hydroxy resinous materials can range fromabout 1:2 on up to about 2:1. The precise intended application of thecoating composition or adhesive composition often will dictate thisratio or isocyanate index.

The radiation curable urethane can be utilized as a coating compositionor an adhesive composition to coat and/or to bond substrates. Theradiation curable urethane composition may contain solvents, fillers,extenders and other functional additives depending upon the specificapplication. Solvents include ketones such as MEK and MIBK, aromaticsolvents such a toluene and xylene, aliphatic solvents such as hexaneand cyclohexane, esters such as ethyl acetate and other solvents such asTHF. The solvents may be used in an amount from about 20% to about 80%by weight of the final composition. The radiation curable urethanecomposition additionally can contain opacifying pigments and inertextenders such as, for example, titanium dioxide, zinc oxide, clays suchas kaolinite clays, silica, talc, carbon or graphite (e.g. forconductive coatings), and the like. Additionally, the compositions cancontain tinctorial pigments, corrosion-inhibiting pigments, and avariety of agents typically found in coating compositions. Suchadditional additives include, for example, surfactants, flow or levelingagents, pigment dispersants, and the like.

The coating method involves applying a coating composition comprisingthe disclosed radiation curable urethane to the surface of a substrateor article then irradiating the coated substrate or coated article withradiation to cure the coating composition containing the UV curableurethane. The type or composition of the article or substrate is notlimited. The article or substrate can be glass, wood, metal, plastic,ceramic, and stone.

Specific examples of substrates include iron, steel, aluminum, copper,galvanized steel, zinc, and the like. Additionally, the coatingcomposition can be applied to wood, fiberboard, RIM (reaction injectionmolding urethanes), SMC (sheet molding compound), vinyl, acrylic, orother polymeric or plastic material, paper, textile, leather and thelike. Since the coating compositions can be cured at room temperature,thermal damage to thermally-sensitive substrates is not a limitation onuse of the coating compositions of the present disclosure. However,heating at conventional curing temperatures may even be practiced onoccasion. It should be understood that the present disclosure can beapplied to primers, intermediate coats, and top coats, substantiallyindependent of film thickness. In fact, the present disclosure mayprovide the ability to formulate a single coating which can functionboth as a primer and as a top coat (unicoat system).

The present disclosure also involves any substrate or article producedby the coating method described above.

The disclosure involves adhesive compositions comprising the radiationcurable urethane. The adhesive composition is not limited and can be anyformulation where radiation curing techniques can be utilized. The fastcuring afforded by the radiation curable formulation is desirable inmany urethane adhesive applications that have traditionally requiredlong cure times. This can lead to higher production rates and lowerproduction costs.

The disclosed adhesive composition can be used to bond substratestogether. The method involves applying the disclosed radiation curableurethane adhesive composition to at least one of at least twosubstrates, then joining the at least two substrates with the radiationcurable urethane adhesive composition between the substrates forming alaminate then irradiating the adhesive composition with radiation tocure the adhesive composition thus bonding the substrates.Alternatively, the radiation curable adhesive composition can be appliedto one of the at least two substrates then irradiated followed byjointing the second substrate to the first substrate with the irradiatedcomposition in between. Multiple substrates can also be bonded with thistechnique. Examples include multilayer flexible laminated packaging.

The substrates can be and rigid and/or flexible material. If theradiation curable composition is irradiated after the two substrates arejointed, one of the substrates should be at least partially transparentto radiation so that the adhesive composition can cure. If the radiationcurable composition is irradiated before joining the substrates then thesubstrates do not need to be transparent to radiation. The substratescan be any type of material and typically include isocyanate foam,plastic, fiberglass, polystyrene foam, flexible plastic, rigid plastic,plastic packaging glass, wood, metal, plastic, ceramic, stone, paper,textile, leather, iron, steel, aluminum, copper and combinationsthereof.

Specific types of plastic, both rigid and flexible, include polyethylene(PE), polypropylene (PP), PE/PP, low density PE, linear low density PE,high density PE polyisobutene, polyvinylchloride, polyvinylacetatecopolymer (EVA), nylon, polyester, mylar, polystyrene styrenic polymers,polycarbonate, acrylic polymers, acetal polymers, PET polymers, ABSpolymers, fluoropolymers, PFTE, HIPS, EVOH, PP/EVOH, polyketones,polyimides, sulfone polymers and polysulfide polymers.

Other examples of substrates include silicon oxide or aluminum oxidecoated plastic such as polyester, nylon and PP.

For flexible substrates, substrate thickness can range from about 0.1mil to about 50 mil and more typically from about 1 mil to about 20 mil.

The disclosure also involves articles bonded together with the adhesivecomposition such as laminated products.

The following example is for illustrative purposes only and is notintended to limit the scope of the claims. The example involvesproducing a laminated flexible packaging utilizing the disclosedcomposition.

In general, the flexible packaging is produced by compounding thecomponents of the urethane adhesive with a mixing device such as astandard mixing blade or a static mixer. Typically, the compoundedurethane adhesive is applied to a laminating head and the adhesive istransferred to a flexible substrate. The laminating head is typicallyset to a temperature from about 25° C. to about 50° C., more typicallyfrom about 25° C. to about 45° C. The coat thickness of the adhesiveapplied onto the substrate is typically from about 0.01 mils to about0.250 mils, more typically from about 0.03 mils to about 0.175 mils andeven more typically from about 0.05 to about 0.150 mils.

After the adhesive is applied to the first flexible substrate (primaryfilm), the first flexible substrate is married to a second flexiblesubstrate (secondary film) with the adhesive layer between the primaryand secondary film. The flexible laminate has the layered structureprimary film/adhesive/secondary film. This process can be repeated toform a multiple layer laminate. For example, the secondary layer of theflexible laminate about can have urethane adhesive applied to itssurface and then a tertiary film can be married to the flexible laminateto form the laminated structure primary film/adhesive/secondaryfilm/adhesive/tertiary film. This process can be repeated to achieve anydesired number of layers in any desired order of flexible substrates(films).

Once the at least two flexible substrates are married together, to forma flexible laminate, the laminate is passed through a nip between tworolls under pressure. One or both of the rolls may be heated. The nippressure typically is about 0.1 pli to about 100 pli. One or both of therolls may be heated to about 25° C. to about 100° C., more typicallyfrom about 25° C. to about 60° C. and even more typically from about 25°C. to about 50° C.

For multiple layer laminates (more than 2 flexible substrates) thelaminate can be passed through the nip for each succeeding layer ofadhesive and flexible substrate or the entire multiple flexible laminatecan be formed first then passed through the nip. The urethane adhesiveis then allowed to cure by exposure to radiation. Exposure to radiationcauses the mercaptan and olefinic compound to react thus eliminating theblocking effect of the mercaptan. The de-blocked catalyst can thenquickly cure the urethane adhesive.

The flexible substrate coated with the urethane adhesive is subjected toUV radiation before the nipping process. Some heat may be applied tofacilitate adhesive wet out. The following non-limiting exampleillustrates one embodiment of the disclosure.

Laminated packaging is prepared using the general procedures describedabove. Two laminated packaging examples are prepared and include anexample (Example 1) which is produced with a commercially availableurethane adhesive (Rohm and Haas C33/1390®) and an example (Example 2)produced with a urethane adhesive containing the disclosed composition.Processing conditions for the laminations and the flexible substrates(films) are given below in Table 1. The urethane adhesive formulationfor Example 2 is given in Table 2.

TABLE 1 Process conditions for producing the flexible laminatedpackaging. Process Parameters Application roll temperature 35° C. NIProll temperature 45° C. Line speed   40 fpm Adhesive coat thickness 0.11mils Flexible substrates (films) Primary film  48 g PET Secondary film2.0 mil LDPE

TABLE 2 UrethaneAdhesive Formulation used for Example 2 UrethaneFormulation 2 Polyisocyanate, wt % Hexamethylene Diisocyanate Trimer 100Polyfunctional Curative, wt % Polypropylene glycol 57.75 Caster Oil 35.4Polypropylene Glycol Trimer 4.9 Dibutyl Tin Dilaurate (Catalyst) 0.04Mercapto Silane (Blocking Agent) 0.32 Diallyl Phthalate (OlefinicCompound) 1.50

A Nordmeccanica® Super Simplex SL Laminator is used to laminate thefilms. The two parts of the urethane composition (polyisocyanate andpolyfunctional curative) are mixed in the ratio 1:1.9 using meter-mixequipment before coating and lamination. The laminated flexiblepackaging for the two examples are prepared as described above exceptExample 2 containing the disclosed composition is exposed to UVradiation just before the nips. The adhesive in Example 2 (disclosedcomposition) cures in less than one day. In contrast, the adhesive inExample 1 takes 7 days to cure. These results demonstrate the ability ofthe disclosed composition to provide on-demand performance.

Next, the urethane compositions described above (Examples 1 and 2) areused as coatings. The urethane compositions are coated on aluminumpanels at a film thickness of 5 mil. Example 2 is cured with UVradiation immediately after coating. Both samples are tested 24 hoursafter coating. The samples are tested by cross-hatch testing usingScotch 600® tape and rated by ASTM D3359. The results are given in Table3.

TABLE 3 Coating results for Examples 1 and 2. Example 2 (UV Cured)Example 1 2B (15-35%) 0B (100%) 1B (35-65%) 0B (100%) 1B (35-65%) 0B(100%) MEK double rubs >200 MEK double rubs 150-180

The results show that the discussed composition provides goodperformance as a coating composition and gives good performance relativeto the non-radiation cured (Example 1) composition.

Next, the disclosed urethane composition described above (Example 2) isused to laminate wood (pine) substrates and sheet molded compositesubstrates (SMC) (Ashland Phase Beta). The urethane composition isapplied to one side of two substrates, irradiated with UV radiation thenthe substrates are joined with the urethane composition in between. Thejoined substrates are pressed at 125 psi for 48 hours. The woodsubstrate showed an average lap shear strength of 337 psi and the SMCsubstrates showed a strength of 497 psi. The results demonstrate thatthe disclosed composition can be used in as an adhesive in laminatingrigid substrates.

The term “comprising” (and its grammatical variations) as used herein isused in the inclusive sense of “having” or “including” and not in theexclusive sense of “consisting only of”. The terms “a” and “the” as usedherein are understood to encompass the plural as well as the singular.

The foregoing description illustrates and describes the presentdisclosure. Additionally, the disclosure shows and describes only thepreferred embodiments of the disclosure, but, as mentioned above, it isto be understood that it is capable of changes or modifications withinthe scope of the concept as expressed herein, commensurate with theabove teachings and/or skill or knowledge of the relevant art. Theembodiments described hereinabove are further intended to explain bestmodes known of practicing the invention and to enable others skilled inthe art to utilize the disclosure in such, or other, embodiments andwith the various modification required by the particular applications oruses disclosed herein. Accordingly, the description is not intended tolimit the invention to the form disclosed herein. Also, it is intendedthat the appended claims be construed to include alternativeembodiments.

All publications, patents and patent applications cited in thisspecification are herein incorporated by reference, and for any and allpurposes, as if each individual publication, patent or patentapplication were specifically and individually indicated to beincorporated by reference. In the case of inconsistencies, the presentdisclosure will prevail.

1. (canceled)
 2. The composition as claimed in claim 6, wherein themetal compound is selected from the group consisting of a tin compound,a bismuth compound, a germanium compound, a cobalt compound, a manganesecompound and mixtures thereof.
 3. The composition as claimed in claim 6,wherein the mercapto compound is selected from the group consisting oftrimethylol propane tri-(3-mercapto propionate), pentaerythritoltetra-(3-mercapto propionate), glycol di-(3-mercapto propionate), glycoldimercapto acetate, trimethylol propane trithioglycolate, mercaptodiethyl ether, ethane dithiol, thiolactic acid, mercapto propionic acid,mercapto propionic acid esters, thiophenol, thio acetic acid, 2-mercaptoethanol, 1,4-butanedithiol, 2,3-dimercapto propanol,toluene-3,4-dithiol, alpha,alpha′-dimercapto-para-xylene, thiosalicylicacid, mercapto acetic acid, dodecane dithiol, didodecane dithiol,di-thio phenol, di-para-chlorothiophenol, dimercapto benzothiazole,3,4-dimercapto toluene, allyl mercaptan, benzyl mercaptan, 1,6-hexanedithiol, 1-octane thiol, para-thiocresol, 2,3,5,6-tetrafluorothiophenol,cyclohexyl mercaptan, methylthioglycolate, mercapto pyridines,dithioerythritol, 6-ethoxy-2-mercaptobenzothiazole, d-limonenedimercaptan, γ-mercapto silane and mixtures thereof.
 4. The compositionas claimed in claim 6, wherein the olefinic compound is selected fromthe group consisting of diallyl phthalate, acrylic acid, methacrylicacid, alkyl acrylate, alkyl methacrylate, acrylamide and mixturesthereof.
 5. The composition as claimed in claim 6, wherein the metalcompound is selected from the group consisting of dibutyltindilaurate,stannous acetate, stannic oxide, stannous octoate, dibutyltin dioctoate,tin mercaptides, stannous citrate, stannous oxylate, stannous chloride,stannic chloride, tetra-phenyl tin, tetra-butyl tin, tri-n-butyl tin,tri-n-butyl tin acetate, dialkyl tin dicarboxylates, dimethyl tindichloride, bismuth tricarboxylates, bismuth nitrate, bismuth halides,bismuth sulfide, basic bismuth dicarboxylates, and mixtures thereof. 6.A radiation curable urethane composition comprising a) a compositioncapable of radiation activated catalysis comprising a metal compound, amercapto compound; and an olefinic compound; b) hydroxyl compound; andc) an isocyanate compound.
 7. The radiation curable urethane compositionas claimed in claim 6, wherein the hydroxyl compound is a polyol.
 8. Theradiation curable urethane composition as claimed in claim 7, whereinthe polyol is an aliphatic polyol.
 9. The radiation curable urethanecomposition as claimed in claim 6, wherein the hydroxyl is selected fromthe group consisting of hydroxypolyester, hydroxypolyethers,hydroxypolythioester, hydroxypolyacetal, hydroxypolycarbonate, dimericfatty alcohol, esteramide, polyetherpolyol, polyesterpolyol,polycarbonatepolyol, ethylene glycol, triethylene glycol, tetraethyleneglycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol,1,3-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol,1,4-bis-(hydroxymethyl)-cyclohexane,bis-(hydroxymethyl)-(tricycle-[5.2.1.0^(2.6)]-decane,1,4-bis-(2-hydroxyethoxy)-benzene, 2-methyl-1,3-propanediol,2,2,4-trimethylpentanediol, 2-ethyl-1,3-hexanediol, dipropylene glycol,polypropylene glycols, dibutylene glycol, polybutylene glycols,bisphenol A, tetra-bromobisphenol A, glycerol, trimethylolpropane,1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol, quinitol,mannitol, sorbitol, methylglycoside 1,4:3,6-dianhydrohexitol andmixtures thereof.
 10. The radiation curable urethane composition asclaimed in claim 6, wherein the isocyanate compound is a polyisocyanate.11. The radiation curable urethane composition as claimed in claim 10,wherein the polyisocyanate is an aliphatic polyisocyanate.
 12. Theradiation curable urethane composition as claimed in claim 6, whereinthe isocyanate compound is selected from the group consisting ofhexamethylene diisocyanate, 4,4′-toluene diisocyanate (TDI),diphenylmethane diisocyanate (MDI), polymethyl polphenyl isocyanate(Polymeric MDI or PAPI), m-phenylene diisocyanates, p-phenylenediisocyanates, bitolylene diisocyanate, triphenylmethane tri isocyanate,tris-(4-isocyanatophenyl)thiophosphate, cyclohexane diisocyanate (CHIN),bis-(isocyanatomethyl)cyclohexane (H₆XDI), dicyclohexylmethanediisocyanate (H₁₂MDI), trimethylhexane diisocyanate, dimer aciddiisocyanate (DDI), dicyclohexylmethane diisocyanate, dimethylderivatives of dicyclohexylmethane diisocyanate, trimethyl hexamethylenediisocyanate, lysine diisocyanate, methyl ester of lysine diisocyanate,isophorone diisocyanate, methyl cyclohexane diisocyanate,1,5-naphthalene diisocyanate, triphenyl methane triisocyanate, xylenediisocyanate, methyl derivatives of xylene diisocyanate, hydrogenatedderivatives of xylene diisocyanate, polymethylene polyphenylisocyanates, chlorophenylene-2,4-diisocyanate and mixtures thereof. 13.A coating composition comprising the radiation curable urethanecomposition as claimed in claim
 6. 14. A method of coating an articlecomprising applying the coating composition as claimed in claim 13 tothe surface of the article then irradiating the coated article withradiation to cure the coating composition.
 15. The method of coating anarticle as claimed in claim 14, wherein the article is selected from thegroup consisting of glass, wood, metal, plastic, ceramic, stone, iron,steel, aluminum, copper, galvanized steel, zinc, wood, fiberboard,reaction injection molding urethanes, sheet molding compound, vinyl,acrylic, polymeric material, plastic material, paper, textile, leatherand combinations thereof.
 16. A coated article produced by the method asclaimed in claim
 14. 17. An adhesive composition comprising theradiation curable urethane composition as claimed in claim
 6. 18. Amethod of bonding at least two substrates comprising applying theadhesive composition as claimed in claim 17 to at least one of the atleast two substrates, joining the at least two substrates with theadhesive composition between the at least two substrates to form alaminate, irradiating the laminate with radiation and then allowing theadhesive composition to cure.
 19. The method of bonding at least twosubstrates as claimed in claim 18, wherein the at least two substratesare both rigid, both flexible or one is flexible and one is rigid. 20.The method of bonding at least two substrates as claimed in claim 19wherein the at least two substrates are selected from the groupconsisting of isocyanate foam, plastic, fiberglass, polystyrene foam,flexible plastic, plastic packaging, plastic sheeting, wood, metal,plastic, ceramic, stone, paper, textile, leather, iron, steel, aluminum,copper and combinations thereof.
 21. An article produced by the methodof bonding at least two substrates as claimed in claim
 18. 22. Themethod of bonding at least two substrates as claimed in claim 19 whereinthe at least two substrates are plastic and wherein the plastic isselected from the group consisting of polyethylene (PE), polypropylene(PP), PE/PP, low density PE, linear low density PE, high density PEpolyisobutene, polyvinylchloride, polyvinylacetate copolymer (EVA),nylon, polyester, mylar, polystyrene styrenic polymers, polycarbonate,acrylic polymers, acetal polymers, PET polymers, ABS polymers,fluoropolymers, PFTE, HIPS, EVOH, PP/EVOH, polyketones, polyimides,sulfone polymers, polysulfide polymers and combinations thereof.
 23. Thecomposition as claimed in claim 6, wherein the radiation is actinicradiation or e-beam radiation.
 24. The composition as claimed in claim6, wherein the radiation is UV radiation.
 25. A method of bonding atleast two substrates comprising applying the adhesive composition asclaimed in claim 17 to at least one of the at least two substrates,irradiating the at least one of the at least two substrates with theadhesive composition with radiation, joining the at least two substrateswith the adhesive composition between the at least two substrates toform a laminate and then allowing the adhesive composition to cure.